"All of Asia has had such huge gains, so we had to have a correction sooner or later, " said Shane Oliver, head of investment strategy at AMP Capital in Sydney.

WSJ: Nikkei Drops 7.3%

"Commodity prices have fallen and inflation has come in less than expected, and of course the Australian dollar through all of that has remained surprisingly strong, " said Shane Oliver, chief economist with AMP Capital Investors.

BBC: BHP Billiton Western Australia iron ore mine

"The feeling is that the euro crisis could be back and that you could see full on contagion, that is why you're seeing the market reaction today, " said Shane Oliver, head of investment strategy and chief economist at AMP Capital in Sydney.

WSJ: Asian Shares Fall Amid Cyprus Bailout Concerns